Help with a ID please

[JW20VT]

have these on some of my live rock , i have searched through the guides and only found one place online with this picture but no answer for the guy either.

this is not my pic but exactly what im trying to ID... Im new but thinking filter feeder??
ill feel like a complete fool if its something obviously bad and ive skimmed over it in my research

Again , this is not my personal picture but its the best shot ive seen of this , better than any i've gotten to try and post

 

[manbeast]

Pineapple sponge, completely harmless filter feeder, their numbers seem to swell and decline on their own schedule so sometimes you'll wonder where they are all coming from and a month later you'll wonder where they all went. Nothing to worry about

 

[JW20VT]

very cool , thank you very much

i have them randomly scattered all over my rock al different sizes. was starting to get worried it was something bad cause ive noticed more and more